Author Topic: ANSMANN Got wild 4400mA charging power for AA NiMH !!  (Read 14775 times)

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Offline ipman

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Re: ANSMANN Got wild 4400mA charging power for AA NiMH !!
« Reply #25 on: July 15, 2011, 10:38:40 am »
Let me describe the ideal charger:
-independent channels for each cell
-charge termination methods: minus delta V and termal, timer cut-off user-programable
-cells spaced enough to ensure good ventilation
-charging current programable with 1mA resolution
-cutoff based on voltage measurement with at leas 3 decimals, ideally 4 or more
-pulse-based charging, some say even negative pulse charging
-power supply independent from main body, to reduce heat dissiapation
-very thick leads to cells

Others, feel free to add features tot that list.

MH-C801D is not idea because: it does not allow you to select charging rates as fine as required (at most 100mA resolution). It does not have a programable timer. Cells are quite crowded.
« Last Edit: July 15, 2011, 11:02:05 am by ipman »
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Offline Mechatrommer

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Re: ANSMANN Got wild 4400mA charging power for AA NiMH !!
« Reply #26 on: July 15, 2011, 02:35:04 pm »
-timer cut-off user-programable
-charging current programable with 1mA resolution
-MH-C801D: Cells are quite crowded.
ok good points there, the others ore classic spec. i still feel the batteries got too hot when complete charging, maybe another reason for "premature death" of batteries. i'll kiv the C9000.
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Offline Kiriakos-GRTopic starter

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Re: ANSMANN Got wild 4400mA charging power for AA NiMH !!
« Reply #27 on: July 15, 2011, 03:37:39 pm »
Well there is a good secret that the companies who make all those Low Self Discharge NiMH batteries,
they do not say it to you.
Their specifications stands for environmental temperature of 20C Max !! 
and another one... every batteries are mortal! 

I love your humor... but the batteries are not that sensitive as you can probably think.
They are wild animals LOL .

The NiMH chargers are 20 years old technology,  only for the batteries there is some room for improvements,
and due the fact that we have specific ranges in their capacity,  there is no need for endless increments of the charging current.
The only excuse for having all those increments, are to own worthless dead cheap batteries, that you do not trust to charge them at the named specs.
Many old NiMH batteries that was made with low capacity, they are not here, they had become dust.
   
The AAA rechargeable have gain a tiny market segment, I use AAA only at my small Office desk LED light,
at the remote control of my Scorpio moto alarm, and today on my Agilent U1272A.

About AA, their capacity starts today from 2100mAh to 2850mAh and that's it.
There is no need for fancy chargers , but for healthy chargers.

And if you worry about temperature, it costs you nothing to add one small fan on your charger.
Especially if you live in hot climates.

Every NiMH it should retain 1.34V - 1.38V  max as soon it removed from the charger and after of two hours cooling down period.
If you get higher voltage, the charger is damaged and overcharges the batteries.

 

Offline ivan747

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Re: ANSMANN Got wild 4400mA charging power for AA NiMH !!
« Reply #28 on: July 18, 2011, 05:58:59 am »
Let me describe the ideal charger:
-independent channels for each cell
-charge termination methods: minus delta V and termal, timer cut-off user-programable
-cells spaced enough to ensure good ventilation
-charging current programable with 1mA resolution
-cutoff based on voltage measurement with at leas 3 decimals, ideally 4 or more
-pulse-based charging, some say even negative pulse charging
-power supply independent from main body, to reduce heat dissiapation
-very thick leads to cells

Others, feel free to add features tot that list.

MH-C801D is not idea because: it does not allow you to select charging rates as fine as required (at most 100mA resolution). It does not have a programable timer. Cells are quite crowded.

I am inclined to think people will crank this up to it's maximum charging rate. They crank up the air conditioner's temperature and think they can control the A/C accurately with the flow speed. On rainy days it cools so much they turn it off. SO annoying. They think if I turn it 5 degrees to the other side it starts heating everything or wastes the same amount of fuel or something... Well, that's just here in DR.

100mAh adjustment is more realistic, since most batteries are rated like this and 50mAh of difference is not a big deal. I don't see why a battery charger needs a programmable timer. Just have sense the temperature and if things get hot, just stop charging the battery. The voltage cuttoff is not likely to be precise on cheaper products. It can all be implemented in an ASIC, although I don't know about designing IC's.

Multichemistry with automatic detection would be awesome, although I have no idea if that is even possible. Alkaline charging can be handy, but not recommended. Also, it will cause confusion.
 

Offline ipman

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Re: ANSMANN Got wild 4400mA charging power for AA NiMH !!
« Reply #29 on: July 18, 2011, 07:32:52 am »
The timer was added there not as requirement, but as a "nice to have feature".
Sure, some chargers have thermal protection, but they don't react allways, or the threshold is not user-programmable. In this case the timer cames handy.
Multichemistry auto-detection is a bit tricky. Along with dangers associated with Lithium-something batteries which can burn or explode, it' even dangerous.
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